Variable output burner for liquid fuel with pressure pulverization



Sept. 11, 1956 A. F. CHARASSE 2,7

VARIABLE OUTPUT BURNER FOR LIQUID FUEL WITH PRESSURE PULVERIZATION FiledApril 9, 1953 Ewen 1 R Hugus r: Emma (imzznsss a/m 1 W VARIABLE OUTPUTBURNER FOR LIQUID FUEL WITH PRESSURE PULVE'RIZATI'ON Auguste F rangoisCharasse, Marseille, France Application April 9, 1953, Serial No.347,780

Claims priority, application France May 13,1952.

2 Claims. ((11. 299118) Some burners used for heating with mazout, whichatomize the fuel by compression (that is to say mostly those which areat present employed in large installations and in the marine art) cannotbe adjusted. Their output is constant and to alter the amount of heatingrequires periodical extinction of some of the burners which constitutethe heating group. For example, there is obtained a reduction of heatingof 20% if one burner out of five is extinguished. This is not a greatdisadvantage where all the burners heat the same. hearth; when theburners each heat an individual hearth, it is not possible to adjust thegeneral heating except by successively changing the burners, that is tosay by replacing them by others which carry firing heads of differentdimensions. This requires the successive extinction of burners to bechanged, manipulation of valve gear, replacement, relighting, etc., andentails a great loss of time. Even when the operation is carried out bya specialist trained and used to it (who may not take much longer than aminute per apparatus) a change of speed on an oil-fired ship with twelveburners is an operation which takes a relatively long time.

The reasons which have made it impossible hitherto to adjust these knownburners reside in the construction of their firing heads. These firingheads, which are very simple, comprise forward of the nozzle opening(these words forward of being considered as on the path of the fuelbefore the latter has reached the nozzle opening) a small circularchamber which is fed by one or more small inlet pipes, these latterbeing arranged in such a manner that the liquid fuel entering (eithertangentially or at any other suitable angle) arrives in this, chamber ina state of turbulence arising from the effect of the feed pressure; thisturbulence causes the jet, passing out through the nozzle (which issituated in the middle of the said chamber), to be rotated in such amanner that the liquid which is expelled is under the influence of twoforces: one due to the pressure thrusts it forward axially of thenozzle, whilst the other due to the rotation causes dispersion bycentrifugal force. I

Thus it is impossible to adjust the flow of fuel by altering thepressure of the fuel pumps because the result of a reduction of pressurewould be a slowing down of the fuel in the inlet pipe or pipes whichfeed the. turbulence chamber and causev the turbulence, and thus wouldimpair the atomisation.

If it were attempted to construct a firing head. with variable nozzleopening, the solution would be similarly ineffective because it againwould not be possible to use this variation of section of the burnernozzle in order to vary the output of the burner without prejudicing theatomisation. It is in fact evident that when the nozzle orifice is ofreduced section, the output will beautomatically reduced also and as nomore liquid can enter into the small turbulence chamber (which feeds thenozzle) then comes out of it, the inlet pipe or pipes through which theliquid is introduced into the chamber would only let through liquid at alower speed, as a nited States Patent 2 result of which. there would bea reduction of the dispersive centrifugal force.

The object of the present invention is to. provide a construction offiring head the output of which is variable without prejudice to theatomisation, the fineness, of which remains constant.

According to the. invention, this is achieved by varying in proportionthe section ofthe outlet nozzle orifice and the totalsection ofthe inletpipe or pipes which introduce the fuel into the turbulence chamber,this, proportionate variation being carried out in. such a manner thatat any point in the range of adjustment, the ratio between these twosections. is always within permissible limits. for obtaining a suitabledegree of dispersion.

The ratio between these sections is basically the same as that ofcompression pulversi'zers. There is an optimum ratio which it isnecessary to conserve, andv it is to be, noted that when the totalorifice of the inlet pipe or pipes becomes greater than is necessarywith respect to the outlet. nozzle orifice, the. speed of rotation.diminishes, whilst. when it becomes. smaller, this speed subsists butthe pressure falls in the chamber leading to axial slowing of theemergent fuel.

The varying of the two sections in proportion permits to, maintain therelationship between. the linear speed projecting, the liquid forward.and the speed of rotation which causes the dispersion constant.

The operation of an apparatus thus constructed reproduces, at. eachposition of adjustment, the usual functioning of a mazout compressionburner in. which, the. same modification of the sections would have beenobtained by changing the components of the burner. In, effect, thechanging of the washer-like nozzle elements, in a burner of known kind,is nothing more than the putting in position in the apparatus of a newturbulence chamber comprising two orifices of shaping different fromthat of the preceding. chamber, but of the same proportion as those ofsaid preceding chamber.

At a predetermined pressure it is not possible whilst conserving goodoperation, to vary the section of' only one orifice of the two; ineffect, the enlargingof the nozzle orifice or the lessening of the totalorifice of the inlet pipe or pipes will not slow down the rotation butwill cause the pressure in the chamber to. drop, as a result of whichthere is a diminuation or elimination of the axial pressure. As aresult, the apparatus drips or spits to the side; the contraryoperation, consisting in the reduction of the, nozzle orifice or theenlarging of the total orifice of the inlet pipe or pipes would increasethe pressure in the chamber but would cause there a diminution of thespeed of turbulence, as a result of which there would be a lessening ofthe, dispersive force and thus projection forwardly of a jet which wasonly slightly dispersed, or not dispersed at all- An embodiment ofburner in accordance with the in,- vention is hereinafter particularlydescribed with reference to the accompanying drawing, wherein: Fig. 1 isa longitudinal central vertical section of the head of a burner; Figs. 2to 6 show in separated position some of the members constituting theburner, Fig. 2. showing a cap, Fig. 3 showing, a socket, Fig. 4 showingan outlet nozzle, Fig. 5 showing a turbulence chamber, and Fig. 6showing a valve member and threaded stem therefor; Figs. 7 and 8 arerespectively an elevation and a central vertical section of a threadedboss receiving the valve member; Fig. 9 shows part of a guide socket atthe end of a control rod for the valve; Fig. 10 is an elevation of partof a drive. member, and completes the element shown in Fig. 6'; Fig. 11.shows the forked end of the valve control' rod, to engage with theelement of Fig. 10; Figs. 12 and 13 are respectively a front elevationand a perspective view of the turbulence chamber shown also in Fig. 5.

within the socket 2. Between the front face 7 of the turbulence chamberand the cap 15 is disposed a washerlike member 13 (see Fig. 4) having init a bore 14 consisting of a frusto-conical part tapering to acylindrical part, considered in the direction of flow of the fuel asexplained hereinafter. The cap serves to clamp the members 13, 5 and 3tightly together Within the socket 2. The turbulence chamber 5has acylindrical axial bore 6 and also a number of radial channels 8 whichlead into said bore from the space remaining outside the turbulencechamber 5 as the latter lies within the bore of the socket 2.

In the cylindrical bore of the turbulence chamber is disposed, inlongitudinally slidable manner, a cylindrical valve member 9 formedintegrally at the end of a threaded stem 10 carried at the end of ashort shaft 11 terminating at its other end in a drive key member 20.The threaded stem 10 is rotatably engaged in the internal threading ofthe boss 3 so that rotation of the assembly 9, 10, 11 and 19 causesaxial movement of the valve member 9 with respect to the turbulencechamber 5 within which it is disposed. A rotatable axial control rod 16,connected to any suitable operating handle (not shown) to the right ofFig. 1, has at its end a guide socket 20 and in said socket a pair offork arms 17 adapted to engage with the drive key member 20. It will beapparent that as the rod 16 is rotated, the valve member 9 will beshifted axially towards or away from the washer-like outlet nozzlemember 13 according to the direction of rotation.

On the end of the valve member 9 adjacent to the washer-like member 13there is disposed a cylindrical closure element 12 the diameter of whichcorresponds to the diameter of the cylindrical portion of the washermember 13, its length being such that when the main cylindrical body ofthe valve member 9 has advanced so far to the left (in Fig. 1) as toshut off the radial inlet passages 8 of the turbulence chamber 5, thelefthand end of closure element 12 has traversed the length of thefrusto-conical portion of the bore of the member 13 and has thus closedthe bore thereof against passage of fuel. Similarly, for all positionsof adjustment of the valve member 9 to the left (in Fig. 1) to uncoverthe inlet passages 8 to any degree, the closure element 12 is withdrawninto the frusto-conical part of the bore of the washer-like member 13 toa corresponding extent.

In use, liquid fuel is forced under appropriate high pressure throughthe interior of the casing 18 towards the left-hand end (in Fig. 1) andpasses through the gaps between the flanges 4 to the interior of thesocket 2 and about the outside of the turbulence chamber 5. According tothe degree of opening of the valve member 9 (i. e.

its extent of movement towards the right in Fig. 1) the inlet passages 8will be open to a greater or lesser extent and will allow the fuel underpressure to enter tangentially into the bore of the turbulence chamberfrom whence it flows past the closure element 12 through thefrusto-conical and cylindrical portions of the bore of the washer-likemember 13, being thereafter discharged into the open through the wideopening of the cap 15.

Due to the entry of the liquid fuel into the chamber 5 tangentially andat a high speed because of its pressure, the fuel upon entering assumesa circular motion and, due to the continued supply, is also forcedcontinuously out through the member 13. Thus the stream of fuel emergeswith an axial movement (due to the feed pressure) and also a rotarymovement (due to the action of the chamber 5). This rotary movementgives rise to a high degree of centrifugal force which causes the fuelstream to disperse in an approximately conical manner immediately uponemerging from the burner.

It will be clear that the operation of the burner, and the correctdegree of dispersion, are dependent upon the speed with which the fuelcan enter and leave the turbulence chamber 5. By the arrangement of thevalve member 9, with its closure element 12, acting to close and openboth the inlet and the outlet passages of the atomisation chamber inproportion, it is made possible to have a variable rate of flow of fuelwithout altering the fineness of dispersion of the fuel as it emerges.

I claim:

1. In a burner for liquid fuel, a hollow head having an inlet and anoutlet passage for fuel, a cylindro-conical turbulence chamber in thehead, said chamber having a cylindrical portion of greater diameter intowhich open tangential channels for the entry into the chamber of fuelcoming from the interior of the head, said portion of greater diametercommunicating through a conical portion with a cylindrical outletpassage of smaller diameter, a valve having two cylindrical portions ofdifferent diameter arranged in the chamber, the cylindrical portion ofthe valve of greater diameter being at the same end and of the samelength as the part of the cylindrical chamber into which the tangentialpassages open, said valve being slidable in the chamber to permit thesimultaneous variation, with a constant ratio preserved between them, ofthe flow into said chamber from the tangential passages controlled bythe portion of the valve of greater diameter, and the flow out of thechamber through the annular gap defined between the end of the valveportion of smaller diameter and the commencement of the cylindricaloutlet passage of the head.

2. In a burner for liquid fuel a hollow head having inlet and outletopening means for liquid fuel, an outlet nozzle member in said headhaving a part cylindrical and part frusto-conical bore, the cylindricalportion being arranged after the frusto-conical portion in the directionof flow of the fuel and the frusto-conical portion tapering in thedirection of How to the diameter of the cylindrical portion, anatomisation chamber member secured in the head and having a cylindricalbore of greater diameter than the frusto-conical bore and communicatingtherewith, said chamber member having inlet passage means for entry offuel from the interior of the head tangentially into its cylindricalbore, and a cylindrical valve member slidably and rotatably arranged inthe chamber member and having a coaxial screw-threaded stem threaded inthe head, the valve member having two cylindrical portions of differentchamber and of which the smaller diameter corresponds to the diameter ofthe cylindrical portion of the bore of the outlet nozzle and the greaterdiameter corresponds to the diameter of the cylindrical bore of theatomisation chamber, said valve member being arranged to coact with thesaid cylindrical bore of the outlet nozzle and with the tangential inletpassage means of the chamber member such that axial movement of thevalve member serves to vary the cross-section of the nozzle bore andtangential inlet passage means of the chamber member simultaneously andin proportion.

References Cited in the file of this patent UNITED STATES PATENTS1,102,352 Peabody et al July 5, 1914 1,725,381 Thomas Aug. 20, 1929FOREIGN PATENTS 35,375 Norway July 24, 1922

